Abu is 14, declawed in front, and hasn't had to deal with other cats in quite a few years now. My son had to move back in, and brought his 8 month old male, w/claws. Until about the last month, all was good. Now, Abraham (he is now 14 mos.) chases Abu, grabs his hind quarters with his claws, and takes him down like a tiger would a gazelle. Abu can't defend himself, so I clap loudly, then crate Abraham. After a month of this, Abraham will not stop. If my son planned on staying permanently, I would make him declaw Abraham, then allow whoever to be dominant. Abu's hind quarters are starting to get tender (no signs of infection). I started putting food and water into my bedroom and giving Abu time out breaks too, so Abraham isn't spending as much time in a crate. Abu has even started asking for the time outs! HELP!

I'd suggest just keeping them separated. If your son isn't going to remain a permanent fixture in your house, there is no reason to try and force the integration to work if it's stressing out your senior (who has no way of defending himself). Is it possible to just keep Abu in his own room for now? Or Abraham?

Yes, it's possible, but doesn't seem to work. Neither cat likes their room being their only living area, and they both will get very obnoxious, loud, and Abraham will even start tearing up the room. Hence, the crate.